This is one of the best RPGs I have ever played. I should have bought the Enhanced Edition, but the difference between the two wasn't very clear.

Pros:
-Adult content is completely avoidable
-Very nice music score. It was a different style altogether.
-Game world is believable enough to warrant a sequel (or prequel). The elven language is based on Celtic which was a nice touch (kind of how the elven language in LotR is based on Finnish).
-Flashy combat system that takes some getting used to, but is designed to cater to a more general crowd. You can choose a point and click camera angle like in the old Kings Quest games, or choose a normal 3rd person shoulder view like Oblivion/Morrowind.
-Storyline did many TYPICAL things, but was interesting and appropriately long.
-Good graphics and engine. The only place I really lagged a bit was in the Trade Quarter, but I was playing at max settings on a Geforce 8800 GT.
-The levelup system was more dependent on skills rather than stats -- definite plus. Leveling was not a grind either.
-The alchemy was well-done. It was much more interesting compared to the system from the Elder Scrolls games.

Cons:
-Normal version of the game has a major difference in voice pitch with Geralt in several conversations. I hear the enhanced edition fixed this, but it wasn't a big enough issue to matter for me.
-The glossary/character entries in the journal was a little overdone. The casual player probably doesn't care, but it adds depth to the game nonetheless.
-The game had a few boring parts that involve a lot of running around. The only thing that kept me going was the drive to finish Quest X. While the scenery was well-done, it did not give enough variety to make me explore for the sake of exploring (in Oblivion, it's enjoyable to just run around to see the sights assuming you've done some texture/environment overhauls). In fact, the player was only free to explore places that were pertinent to the various quests. There were also points of no return with the main story which made completing some quests difficult =/
-Somewhat steep learning curve. It didn't bother me, but it might give trouble to casual gamers.
-NPCs have EXCELLENT voice-overs, but their models were often fairly generic. The female NPCs all have the same generic cleavage that you could lose a dog in. It got pretty tiring. A simple face randomizer could have made things a little better.
-The player and the NPCs wear the same clothes most of the time. I think there are about....four....different armors for Geralt (yes, that includes shirt and suspenders). I was disappointed at the variety in that respect. The alternate weapons like daggers are completely useless because they "cannot be used in witcher combat styles." Why give them to a witcher in the first place? The only thing they're good for is selling in town. I've never been disarmed, so they don't even serve as a backup.
-The game menus load slowly, but the game itself is fine. The loading screen will often hang for as long as 15 seconds before bringing up the list of saved games.
-The inventory could have used more organization. I had to give separate space for potions, ingredients, weapon-related stuff, etc. The game should have done it automatically for the player.

Overall I'd give the game a 9/10. It doesn't appeal quite as much to the casual gamer. The hardware requirements are high, and the game is very detailed. It is worth playing if you don't mind all the cursing/sluts/using of women.